Lieutenant Benjamin’s 20-pounder Parrotts were the workhorses of the Union field artillery. But they were puny compared to the fortress and naval guns that Robert P. Parrott “signed” on their breech bands.

“These monsters, largest of rifles to see active service for the Federals, were designed for seacoast, garrison, and naval roles. In service, the big Parrotts punched holes in fortifications and served as deterrent against Confederate ironclads.”